Code detecting means



Aug. 12, 1952 JEROME 2,607,001

CODE DETECTING MEANS Filed March 18, 1947 I0 I B J Y C TB 113- I? v i v 5 2M; .30 c I K15 INVENTOR.

Patented Aug. 12, 1952 CODE DETECTING MEANS Arthur L. Jerome, Edgewood, Pa., assignor to Westinghouse Air Brake Company, a corporation ofPennsylvania Application March 18, 1947, Serial No. 735,391

My invention relates to coded signaling systems and particularly to improved means for detecting the code following operation of a contact employed in such systems.

In coded signaling systems, code following op-- eration of a-track or other relay having a contact .recurrently operatedbetween a first and a second position may be detected by means of a slow release relay and a condenser which are connected so that when the code following relay contact is in its first position, energy is supplied to the condenser, and when the code following relay contact is in its other position, the energy stored in the condenser is supplied to the winding of the slowrelease relay. As a result, when the contact of the code following relay is operating between its two positions in response to the supply of coded energy to the relay winding, the condenser is periodically charged and discharged, the energy at discharge being supplied to the winding of a slow release relay. This relay is selected so that its release time is longer than the time interval between the pulses of energy supplied from 'the condenser so that as long as the code following relay responds to coded energy the contacts of the slow release relay are picked up. If the code following relay contact should remainin its first position for a substantially long time interval, the condenser will be charged, but the circuit for supplying energy from the condenser to the winding of the slow release relay will remaininterrupted'and after a time .interval'thecontacts of the slow releaserelay will release. Similarly, if the code following relay contact should remain in its other position for a substantially long time interval, the condenser will be connected to the winding during the interval, but after the energy stored in the condenser has been dissipated in the winding of the slow release relay, the slow release relay will release its contacts.

From the foregoing it will be seen that the cessation of operation of the contact of the code following relay results in the release of the slow release relay. Circuits for'the control of various functions may be established over contacts of the slow release relay.

If for any reason the movable contact of the code following relayshould engage both of the associated stationary contacts at the same time, energy would be supplied directly to the slow release relay over the bridging contacts, and the circuits controlled over the contacts of the slow releaserglay .might be improperly established.

It .is'an object of my invention to provide im- Y c Claims. (01. '24634) improved means for detecting the code follow-- ing operation of contacts which may be'sub'ject' proved code detecting means arranged so that defects in the contacts of the code following relay will not result in the improper energization of the code detecting means. I Another object of my invention is to provide to misalignment, sticking,etc., that might cause the movable members. of the contacts to 'si'mul taneously engage both of the associated stationary contacts. 7 c I Other objects of my invention and features of novelty will be apparent :from the following description taken in connection with the accompanying drawing.

In practicing my invention, I iliary code following relay, the contacts of which are picked up when and only when the contacts of the principal code following relay are in their first position, and a condenser'which is supplied with energy from a suitable source of direct current by a circuit including a contact of the principal code following relay closed in its first position and, a .front contact of the auxiliary code following relay. When the contacts of the principal code following relay are in their second position and the contacts'of the auxil iary code following relay are released, a cir cult is established to supply the energy previously stored in the condenser to the winding "of a slow release relay. If the contacts of the principal code following relay-are defective so that they simultaneously engage :both of the associated stationary contacts, the auxiliary .code following relay will be picked up and its contact will interrupt the circuit for supplying energy from 'the condenser to the slow release relay to thereby insure that it remains released. I shall describe onelform of code detecting means embodying my invention, and shall then point out the novel features thereof 'in claims.

The accompanying drawing is a diagrammatic view of asectioniof railway track equipped with signaling apparatus employing code detecting means embodying my invention, 1 j

Referring to the accompanying drawing, there is shown therein-a-sectionofrailwaytrack having track rails I and 2; which are separated from the railsof the adjacent sections by the insulated rail jointsx3. Traffic -normal1y=moves through this section from. left-to right,- as indicated by the arrow. A signal's ,'which,'as shown, is of the color lighttype having avgreen'lamp-G and'a'red'lamp R, islocated'a't the entrance-end provide an-au'X of the section, and governs the entrance of traffic into the section.

A conventional type of coded track circuit is shown, including a coding device CT having a contact I which is recurrently operated between a first and a second position, and a track battery TB for supplying energy to the track section, the battery and coding device being located at the right-hand or exit end of the section. At the entrance end of the section, there is provided a code following track relay TR, an auxiliary relay TP of the code following type, a slow release relay HR, a rectifier K, and a condenser Q.

In addition, there is provided at each end of the section, a source of direct current energy, not shown, whose positive and negative terminals are designated B and C, respectively.

With the equipment in its normal condition as shown in the drawing, the coding device CT is continuously connected to terminals B and C of the source, and as a result, its contact I0 is recurrently operated at a selected rate, for instance, 180 times per minute. When the contact I 0 of coding device CT moves to its second or closed position, the track relay TR is supplied with energy by the circuit which is traced from the positive terminal of battery TB, over front contact ID of coding device CT, over section rail I, through the winding of track relay TR and through section rail 2 to the negative terminal of battery TB. On the supply of energy to the winding of relay TR the relay contacts move from their first or released position to their second or picked up position. Accordingly, the movable contact I2 of relay TR is disengaged from its stationary back contact I4, and movable contact I 6 of relay TR is moved into engagement with its stationary front contact I8. After a short time interval, the contact I0 of coding device CT moves to its first or released position, interrupting the supply of energy to track relay TR over section rails I and2, and as a result, the movable contact I2 of relay TR is moved into engagement with its stationary back contact I4 and movable contact I6 of relay TR is disengaged from its stationary front contact I8.

.It will be seen from the foregoing that the supply of impulses of energy to the winding of relay TR cause operation of the contacts I2 and I6 of relay TR. When the movable contact I2 of relay TR releases and engages stationary back contact I4, it establishes a circuit to supply energy to the winding of relay TP. This circuit is traced from terminal'B, over movable contact I2 and stationary back contact ll of relay TR, and through the winding of relayTP to terminal 0. As a result relay TP is energized and its con-. tact 20 is moved from its first or released position. to its second or picked up position. Accordingly, movable contact 20 is moved out of engagement with its stationary back contact 22 and into engagement with its stationary front contact 24. A circuit is thereby established to supply energy to the condenser Q, which circuit is traced from terminal B, over movable contact I2 and stationary back contact I4 of relay TR, through the rectifier K, over stationary front contact 24 and movable contact 20 of relay TP, to the lefthand element of condenser Q, the right-hand element of condenser Q being connected to terminal C. As a result, a charge of energy is built up in the condenser Q.

When the movable contact l2 of relay TR is picked up and disengaged from its stationary back contact I4, the circuits previously traced for supplying energy to the relay TP and the connot fiow through it from the left-hand element of' condenser Q, and as a result, the relay TP re-- leases promptly on picking up of relay IR.

At this time the movable contact I6 of relay TR engages its stationary front contact 18, and a circuit is established for supplying energy from the condenser Q to the winding of the slow release relay HR. This circuit is traced from the left-hand element of condenser Q, over movable contact 20 and stationary back contact 22 of relay TP, and over movable contact I6 and stationary front contact I8 of relay TR, and through the winding of relay HR to terminal C and the right-hand element of condenser Q. As a result, contact 26 of relay HR is picked up and establishes the circuit for supplying energy to the green lamp G of the signal S.

When the movable contact I6 of traclr relay TR is out of engagement with its stationary front contact I8, the supply of energy from condenser Q to the relay HR is interrupted. However, relay HR is slow in releasing its contacts, and the relay is selected so that its release time will bridge the intervals between the supply of impulses to its winding as long as relay TR is operated by coded energy and contact 26 of relay HR will remain picked up at this time.

From the foregoing it will be seen that as long as track relay TR is responding to impulses of energy supplied from the exit end of the track section over track rails I and 2. the relay HR will be picked up, and signal S will display a green aspect, indicating proceed.

I will now assume that a train enters the section proceeding from left to right. The wheels and axles of the train offer a low resistance path to the energy being supplied to the rails I and 2 from the exit end of the section, and as a consequence, the amount of energy received by track relay TR is insufficient for its operation. As'a result, the movable contacts l2 and I6 of relay TR move to their first or released position and remain in that position as long as the train is in the section.

When relay TR releases the relay TP picks up and the supply of energy to relay HR from condenser Q is interrupted by the movable contact I6 of relay TR and also by movable contact 20 of relay TP, and after a short time interval, the contacts of relay I-LR release, interrupting the supply of energy to the green lamp G of signal S, and establishing the circuit for supplying energy to the red lamp R of the signal, indicating stop.

When the train passes out of the section, impulses of coded energy are again supplied to the winding of the track relay TR and its contacts operate in accordance with the impulses of energy received. Each time the contacts of relay TR are in their released or first position, the auxiliary relay TP is picked up, and energy is supplied to the condenser Q, and when the contacts of relay TR are in their picked up or second position, relay TP is released and energy is sup plied from the condenser Q to the relay HR. The supply of energy to the winding of relay HR picks up the contact of'that relay, extinguishing the red lamp R of signal S and lighting the green lampG. The equipment is thus restored to :its normal condition as previously described.

If for any reason the contacts -of relay TR should remain pickedup continuously, it willbe seen that although the condenser Q is'connected to the winding of relay HR continuously, the supply of energy stored in condenser Q will be dissipated in a short time and contact 26 .of relay I-IR will release to thereby light -.the red lamp 'R -o'f signal S.

My invention has a particular riadvantage in detecting-defects in the contacts of the traclcrelay TR which cause the movable contact H to engage its stationary back: contact [4 'at'the same time the movable contact t6 engageslits stationary front contact 18, and cause both contacts to remain-inthat position. If this conditionfarises',

contact -2B-of relay TP-will be picked up and energy will be supplied to condenser Q. .In addition contact I6 of relay TR will engage'its'stationar yfront contact l8 in the circuit for relay HR, but since contact Zll of relay TP is picked up, energy will not besupplied to:relayHR,:and lts'-- contact 26 will remain released 'to lightthe red-lamp R of signal S.

It will be seen therefore that-defects in the contacts of the relay TR cannot-result in the improper display of a green0r"pr0'ceed aspect by signal S, but can only result in the -display of the redorstop indicationbythis signal.

Likewise, any failure of the contacts of relay TP'to :operate as intended cannot result in improper energization of relay HR. If relay .TPi'remains released whenrelay 'IRis released, energy will not :be supplied to the condenser Q and on subsequent picking up of relay TR energy will not be supplied from the condenser to relay HR. Similarly, if when relay TR picks up the relay TP does not release energy will not be supplied from condenser Q to relay HR and it will remain released.

If the-contacts of relay TP are defective so that movable contact 20 simultaneously engages its front contact and itsback contact 22,-the-relay HR will not be improperly energized. Under these conditions, if relay TR is steadily released energy will be supplied to condenser Q, butwill not be supplied through contacts 242022 of relay TP to relay HR since the circuit of relay HR is open at contact l6 of relay TR. If the relay TR is steadily picked up the circuit for supplying energy to condenser Q is open at contact ll of relay TR and energy will not be supplied to the condenser, and will not be supplied through contacts 242 0-22 of relay TP to relay HR and it will remain released and maintain the circuit of the red lamp R.

From the foregoing it will be seen that the relay HR will not be improperly energized as a result of defects in the contacts of the code following track relay TR or of the code following auxiliary relay TP, but will remain released if such a condition arises.

Although I have herein shown and described only one form of code detecting means embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims Without departing from the spirit and scope of my invention. I

Having thus described my invention, what I claim is:

1. In combination, a principal code following relay having contacts movable between a first and a second position in synchronism, an auxiliary code 'following' relay having first andzsecond circuit closing means which are :closed according as said auxiliary code following .relayis' deenergized or energized respectively, a slowreleaserrelay, an asymmetric unit, a condenser, a circuit including a first position contact of said principal code following relay for supplying energy'tothe winding of said auxiliarycode fOllOWing relay, a circuit including said'first position contact of said principal code following relay andsaid secondzcircuit'closing means of said auxiliary relay in series with said asymmetric unit for supplying energy to said condenser, said asymmetric unit being poled so that energy will flow therethrough to charge said condenser, but cannot .fiow therethrough fromsaid condensena circuitincludirig said first circuit closing meansof 'saidauxiliary code following relay and a second Y position contact of said principal code following relay for supplying "energy from said condenser to said slow release relay, and a circuit'controlled by a contact of said slow release relay.

2. In combination, a principal code following relayhavingmovable contacts which'are operated in synchronism between a first and'a second position, an'auxiliarycode following relay having firstand second circuit closing means, circuit means for causing said second circuit closing means of said auxiliary code followingrel'ay to close when the contacts of said principal code following relayloccupy their first'position and to cause said first circuit closing means of said auxiliary codeifollowing relay to close when the contacts of said principal code following relay occupy their second'position, a slow rel'easerelay, a condenser, a vfirst'circuit including a first position contact of saidprincipal code following relay and said second circuit closing means of said auxiliary code following relay for supplying energy to said condenser from'a source of direct current, a second circuit includinga second position contact of said principal code following relay andsaid first circuit closing means of said auxiliary relay for supplyingenergy to said slow release relay from said condenser, means for preventing the energy stored in said condenser from discharging through the winding of said auxiliary relay, and a circuit governed by a contact of said slow release relay.

3. In combination, a first contact recurrently operated between a first and second position, a second contact which is operated to one or the other of two positions according as said first contact is in its first or second position, a third contact which is recurrently operated between a first and a second position in synchronism with said first contact, means for operating said first, second and third contacts in the manner described, a condenser, a first circuit including said first contact closed in its first position in series with said second contact closed in said one position for supplying energy from a suitable source to said condenser, means for preventing the energy stored in said condenser from discharging through said first circuit, a slow release relay, a second circuit including said third contact closed in its second position in series with said second contact closed in said other position for supplyingenergy to said slow release relay from said condenser, and a third circuit governed by the contacts of said slow release relay.

4. In combination, a first, a second, and a third movable contact each of which is movable between a first and a second position, means for recurrently operating said first and second contacts in synchronism between their first and second positions, means for controlling the position of said third contact and effective when said first contact is in its first position to cause movement of said third contact to its second position and when said first contact is in its second position to cause movement of said third contact to its first position, a condenser, a source of direct current, a first circuit effective when said first contact occupies its first position and said third contact occupies its second position to supply energy from said source of direct current to said condenser, means for preventing the energy stored in said condenser from discharging through said first circuit, a slow release relay, a second circuit effective when said second contact occupies its second position-and said third contact occupies its first position for supplying energy from said condenser to said slow release relay, and a circuit governed by a contact of said slow release relay.

5. In combination, a principal code following relay having first and second contacts which are alternately closed at a given code rate, an auxiliary code following relay having first and second circuit closing means which are closed according as said auxiliary relay is deenergized or energized, a slow release relay, an asymmetric unit, a condenser, a source of direct current, a first circuit including said first contact of said principal code following relay to connect said direct current source to a,winding of the auxiliary code following relay to energize that relay, a second circuit including said second circuit closing means of said auxiliary relay and said asymmetric unit to connect said condenser in multiple with said winding of said auxiliary code following relay, said asymmetric unit being poled to permit said condenser to be charged from said source and to block the flow of current from said condenser through said winding of the auxiliary code following relay, and a third circuit including in series said first circuit closing means of said auxiliary code following relay and said second contact of said principal code following relay to connect said condenser to a winding of said slow release relay for recurrently energizing the slow release relay at said given code rate by discharge pulses from the condenser.

6. In safety code detecting apparatus for detecting the recurrent operation of contacts which may be subject to sticking or fusing, in combination, a principal code following relay having first and second contacts which are alternately closed at a given code rate, an auxiliary code following relay having first and second circuit closing means which are closed according as said auxiliary relay is deenergized or energized, a slow release relay, a condenser, a source of direct current, a first circuit including said first contact of said principal code following relay to connect said direct current source to a Winding of the auxiliary code following relay to energize that relay, a second circuit including said second circuit closing means of said auxiliary relay to connect said condenser in multiple with said winding of said auxiliary code following relay, means for preventing the energy stored in said condenser from discharging through the winding of said auxiliary code following relay, and a third cir- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,229,254 Nicholson Jan. 21, 1941 2272:2477 Thompson et a1. Feb. 17, 1942 Fereday Mar. 29, 1949 

